친수성 향상 및 물 분해 활성을 위한 MMT 기반의 촉매화된 3D 접합을 갖는 양극성 막 = Bipolar membranes with MMT-based catalytic 3D junction for enhanced hydrophilicity and water splitting activity

다국어 초록 (Multilingual Abstract)

Bipolar membrane water electrolysis (BPMWE) is a technology that electrically dissociates water at the bipolar membrane (BPM) interface, but has faced limitations, including increased membrane thickness, limited interface area, high overvoltage, and delamination. As a solution, interpenetrating 3D junction is introduced through dual electrospinning to replace the conventional planar interface, and Montmorillonite (MMT) catalyst is introduced through air-spraying. The thin BPMs manufactured through electrospinning formed an entangled interface with increased catalytic sites, thereby improving mechanical stability and reducing the overvoltage required for water dissociation. The transmembrane voltage (TMV) values measured at 100 mA cm-2 (U100) for 3D-­0.57 (0.83 V), manufactured under optimal MMT catalyst dispersion conditions, were 24.5% and 28.0% lower than the U100 values for 2D-­0 (3.39 V) and 3D-­0 (2.96 V), respectively, without catalyst introduction. Furthermore, it exhibited the best performance across the entire I-­V curve, showing a value that was 20.2% lower than that of FBM at U100 (1.04 V). In the high current density (1000 mA cm-2) and long-term stability tests, the TMV of 3D-­0.57 measured after current application showed almost no change. In bipolar membrane electrodialysis (BMED) tests, 3D­-0.57 (5.64 kWh kg-1) demonstrated superior performance over FBM (6.17 kWh kg-1) in terms of energy consumption.

목차 (Table of Contents)

• I. Introduction 1
• II. Literature review 8
• II.1. The concept of BPM 8
• II.1.1. Water dissociation mechanism of BPM 9
• II.1.2. Electrochemical properties of BPMs 11
• II.1.3. Applications of BPMs 15
• II.2. BPM preparations 17
• II.2.1. BPM compositions (CEL, AEL, IL) 17
• II.2.2. Preparation methods 19
• II.2.3. Interface structure 21
• III. Experimental section 23
• III.1. Materials and chemicals 23
• III.2. Synthesis of ionomers (SPEEK, QPPO) 23
• III.3. Dispersive method of montmorillonite 24
• III.4. Preparation of BPMs based on electrospinning method 25
• III.4.1. Preparation of ion exchange membranes 25
• III.4.2. Preparation of BPMs 26
• III.5. Characterization 27
• III.6. Properties of IEMs measurement 27
• III.7. Electrochemical tests 29
• III.8. BMED tests 29
• IV. Results and Discussion 31
• IV.1. Characterizations of the ionomers 31
• IV.2. Characterizations of the MMT (Montmorillonite) catalysts 36
• IV.3. The morphology of nanofibers and BPMs 40
• IV.4. The electrochemical performance of BPMs 42
• IV.5. The high-current-density and long-term stability performances of the BPMs 45
• IV.6. Acid/base production and energy consumption for BMED 46
• V. Conclusion 48
• VI. Future Work 49
• VII. References 50
• 국 문 초 록 62
• List of Publications 65
• List of Presentations 66
• List of Awards 68
• Acknowledgement 69